there seem to be a lot of experts here tonight. (no offense meant.) just that i would agree -- if there is no danger to others, why evacuate? there is clearly a danger, no?

発信者 experts3/12/2011 5:39:30 AM

@helen_cool or does reactor 1 no longer exist?

発信者 Hill100033/12/2011 5:39:32 AM

Reactor 1 exists, but remains in danger.

発信者 Jim3/12/2011 5:42:22 AM

@experts It's probably for precautionary measures. Something probably COULD happen, though unlikely, but they want to get people out of there incase it does happen.

発信者 black_canadian3/12/2011 5:42:48 AM

If Cesium has been detected it is from melt down of rods and containment breach but these are unconfirmed reports by various media outlets feeding each other information.

発信者 C3/12/2011 5:42:56 AM

Nuclear reactor on earthquake fault, and on the water, is the best example of "epic stupid" you could ever find. LMAO when I first saw San Onofre powerplant in So. Calif, wanted to start the Darwin Award for Civil Engineering.

発信者 Academic3/12/2011 5:43:30 AM

They believe that there may be a leak. The last I heard, radiation levels are 8 times the normal amount outside the plant (note that this is nothing. It's eight times an incredibly small number. We get irradiated by other natural sources more than this). However, this could lead to polluted water and other things.

発信者 No worry3/12/2011 5:43:41 AM

Evacuation is a good precaution. It just doesnt hurt to be safe than sorry in this kind of circumstances?

発信者 larry3/12/2011 5:43:43 AM

Three Mile Island and Chernoble had drastically different outcomes. Chernoble breached the containment building and released radiation to the atmosphere. TMI was contained in the vessel. The next containment boudary was the containment building. The media is taking information pieces and sensationalizing it. Yes, there very well could be fuel damage but that doesn't mean that the reactor vessel will be compromised nor will the containment building be compromised. The purpose of these two systems is to contain a problem. The other difference between the PWR reactor and the French designed Chernoble is that the PWR will reduce fission as it heats up, instead of increasing the fission.

発信者 adrenaline_junkie_ff 編集 Reuters_TonyTharakan3/12/2011 5:43:57 AM

People wait for rescue on a building roof in Miyagi Prefecture, northeastern Japan March 12, 2011. REUTERS/Kyodo

発信者 Reuters_TonyTharakan3/12/2011 5:45:13 AM

there ARE a lot of experts here tonight! (i'm not kidding.) happy to be reading comments from some knowledgable people.

発信者 experts3/12/2011 5:45:30 AM

Japanese nuclear authorities say there was a high possibility that nuclear fuel rods at a reactor at Tokyo Electric Power's Daiichi plant may be melting or have melted, according to Jiji news agency.

Experts have said that if the fuel rods have been damaged, it means that it could develop into a breach of the nuclear reactor vessel and the question then becomes one of how strong the containment structure around the vessel is and whether it has been undermined by the earthquake.

発信者 Reuters_david.lalmalsawma3/12/2011 5:47:22 AM

This is Japan, evacuation is the least you can expect in these cases. Everything happening here is always given more attention than anywhere else in the world, let's not read into this evacuation more than it actually mean.

発信者 Francesco Tassari3/12/2011 5:48:12 AM

@Academic The containment building was pretty much built to withstand bombs. Only some extremely direct hit by an earthquake or tsunami wave, neither of which happened, would cause serious damage to the building.

発信者 No worry3/12/2011 5:48:22 AM

Let's hope that this all will end well. Surprised by the low number of casualties so far. Hope it won't increase.

発信者 issakainen3/12/2011 5:48:24 AM

As long as there is reactor melt down, the area around that region is going to be rendered "unsafe" to stay in many years to come. The affected people in that region will and is expected to go through some very tough time. Lets hope the situation in the reactor is and will be under control.

Tokyo Electric Power Company, tells AFP: "We believe the reactor is not melting down or cracking. We are trying to raise the water level."

発信者 Andrew3/12/2011 5:50:16 AM

no reason to think containment should not work as hoped

発信者 Kevin3/12/2011 5:52:12 AM

The danger of a meltdown comes from the fact that these incredibly hot rods come into contact with water. This makes a ton of steam, which builds up pressure in the containment structure. They've already vented some of this pressure and steam into different parts of the building. The main danger now comes from losing the plant, as in not being able to use it any more. The threat of nuclear contamination outside the barrier is pretty small compared to the damage the tsunami and quakes have caused elsewhere.

発信者 No worry3/12/2011 5:52:19 AM

sounds like alot of confusion out there... some say rods are meltings others saying not, i do wonder if the TEPC are under playing the situation and it is worse than they are letting on

発信者 Daily3/12/2011 5:52:23 AM

Meltdown does not render the surrounding land inhabitable. TMI had a partial core melt and people still live and work there.

発信者 RD3/12/2011 5:52:26 AM

Public broadcaster NHK quotes Japanese authorities as saying no need to expand evacuation area around nuke plant

発信者 Reuters_david.lalmalsawma3/12/2011 5:53:07 AM

If cesium has been detected, that means some fuel got very hot (at least 671 C) to vaporize the cesium. That doesn't happen if the fuel is all still properly underwater. So if these fragmentary reports of cesium are right, that's not good. But perhaps someone can please clarify whether this 40-year-old plant actually has a containment dome like modern ones. Some press reports say no, it has only the reactor vessel inside a building. Does someone have a spec-sheet handy for Fukushima 1 Unit 1, please?

発信者 another expert3/12/2011 5:53:29 AM

Having lived in Japan, I can tell you that TEPCO does not have the best reputation for fully informing anyone.

発信者 Jim3/12/2011 5:54:57 AM

@No Worry ?? You just can't build a nuclear reactor on in a major earthquake fault area, nor on a coastline subject to tsunami. How many lives will be lost to prove the obvious?

発信者 Academic3/12/2011 5:55:00 AM

24 years in nuclear power.

発信者 JBF3/12/2011 5:55:05 AM

@Daily ... now you're talking

発信者 xcytble3/12/2011 5:55:14 AM

It's also unclear what the problem is (probably multiple). TEPCO reportedly said it had a backup generator onsite; in principle that should run the valves and controls. However, there were reports of a faulty valve (whether an automatic pressure relief valve or one that needs special operation wasn't clear). We need to await an informed announcement to start understanding what's happening.

発信者 another expert3/12/2011 5:55:23 AM

As long as the containment building can hold back the release of system pressure to internal atmosphere, there will be no or little contamination of the surrounding area. The danger is the plant location (The Coast) and possible structural damage to the containment building.

発信者 Delphic_Dave3/12/2011 5:55:29 AM

@another expert NO... but I heard a report confirming your description of the reactors. These things were built in the 1960's and therefor do NOT benefit from modern construction.

The nuclear power issue hasn't killed anybody yet, and probably won't. How many were killed by the tsunami? Yet there is no coverage on the actual issue

発信者 Stoney3/12/2011 5:57:22 AM

The post just now that the big issue with meltdown is when molten fuel contacts water. There can be hydrogen explosions or steam explosions (like a big foundry accident) or both, and these may rupture any containment. Delphic_Dave says containment has 4-8' thick walls. Modern US reactors have that. It's not at all clear that this 1971 reactor has it, or anything like it.

発信者 another expert3/12/2011 5:57:33 AM

If indeed there is not a modern pressure-tight (save in a large internal explosion) containment structure, then let's stop discussing what it would do it it were there. I hope Helen can ascertain whether it's there or not.

発信者 another expert3/12/2011 5:58:24 AM

japan seems to be the most prepared for 'the big one' as evidenced by no announcements that buildings were toppled down. More lives could have been lost. Should be due to strict bldg codes and tough enforcement. Sympathies and prayers for our asian neighbors.

発信者 steve, manila3/12/2011 5:58:33 AM

No expert but much information is available if one is willing to waste hundreds of hours as I did after 9-11.

発信者 D Morris3/12/2011 5:58:42 AM

@Academic Japan is an area known to get earthquakes. Look up some Youtube videos on the swaying buildings during the quake. They know how to engineer buildings to withstand these kinds of disasters, especially critical buildings like a nuclear plant.

発信者 No worry3/12/2011 5:59:21 AM

Modern Technology.Owes Ecology.An Apology..

発信者 Dhiraj India3/12/2011 5:59:34 AM

companies and authorities will always play down the severity, public and media will often dramatize.. the truth lies somewhere inbetween.. and the situation is long not over, it can get worse after getting better.. lets hope for the best

発信者 MH3/12/2011 5:59:39 AM

That is really to bad. I posted below that the key indicator of an approaching catastrophe would be exposure and melting of the fuel rods. When they opened the vent they must have gotten radiation indicating fuel pellet disintagration.

I tried to post these quotes from the LA times article before, but I don’t think they took.

Qoute: The reactor uses a single cooling loop and does not have a containment dome, but rather uses a smaller containment vessel around the reactor core.

"These first-generation boiling water reactors have the least margin of safety of any reactor design," said Frank N. von Hippel, a Princeton University physicist and former White House advisor.

発信者 D Morris3/12/2011 5:59:53 AM

The posters that are saying the problem is that the fuel rods are coming into contact with water, causing the issue, are completeloy wrong. The issue is that the the water level has dropped, thereby exposing the fuel rods